<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>css3过渡</title>
    <style type="text/css">
    div{
        width: 450px;
        height: 150px;
        margin: 0 auto;
        font-size: 40px;
        border-radius: 10px;
        line-height: 150px;
        text-align: center;
        background-color: yellowgreen;
    }
    div:hover{
        background-color: skyblue;
        color: white;
        transition: all 2s ease;
    }

    </style>
</head>
<body>
    <div>书山有路勤为径</div>
</body>
</html>